Apparatus for assembling parts of electron discharge devices



July 27, 1948.

P. P. DERBY ET 2,445,766

TUS FOR ASSEMBLING PARTS ECTRON DISCHARGE DEVICES APPARA OF EL FiledMarch 28. 1944 A 2 Sheets-Sheet 1 July 27, 1948.

Filed March 28. 1944 P. P. DERBY Erm. 2,445,766 APPARATUS FOR A EHBLINGPARTS OF ELECTRON DI ARGE DEVICES 2 Sheets-Shadi. 2

i@ if Patented July 27,A 1948 APPARATUS FR ASSEMBLING PARTS F ELECTRONDISCHARGE DEVICES Palmer P.Derby, Boston, and Warren M. Robertson,Wakefield, Mass., assignors to Raytheon Manufacturing Company, Newton,Mass., a corporation of Delaware Application March 28, 1944, Serial No.528,442

4` claims. (ci. 113-99) This invention relates to apparatus formanufacturing the anode structure of hyper and ultra high ifrequencyoscillation tubes of the magnetron type.

In tubes of the type. to which the invention relates, the anodestructure comprises a metallic block having a cylindrical cavity and aplurality o'f substantially radially-disposed anode arms projectinginwardly from the wall of said cavity. The space between each pair ofarms or plates constitutes a cavity resonator. The frequency of theoscillations produced by such a device depends upon the geometricalconiiguration of the resonator, and it is important that the anodeplates be accurately spaced so that the cavity resonators will beaccurately matched. The efficiency ofthe device depends in large partupon such accurate. matching of the cavity resonators.

Heretofore difficulties have been encountered in constructing anodestructures of the above type and the art has resorted to relativelycomplicated and expensive arrangements requiring skilled workmanship toinsure the required accuracy. In the copending application of William C.Brown, Serial No. 522,194, filed February 10, 1944, now Patent No.2,433,339, issued Dec. 30, 1947, there is disclosed a method andapparatus which facilitate the construction of such devices and increasethe accuracywith which they may be constructed.

It is an object of the present invention to iurther improve the accuracyof construction and facilitate the manufacture of such devices, so thatthe same may be manufactured by relatively unskilled labor with a highdegree of accuracy.

Devices of the type to which the invention relates may oscillate notonly at 'the desired frequency determined by. the cavity resonatorsdened by each pair of adjacent anodev plates but also as to generatespurious, undesired oscillations due to oscillating circuits provided bynonadjacent anode plates. It has heretofore been Ifound that thesespurious undesired oscillations may be minimized byinterconnecting theinner :ends of alternate anode arms or plates by various strapping`arrangements. Such strapping artion of such anode structures having acomplete strapping arrangement without materially in- Y creasing thecost of manufacture or the labor and skill required as compared withunstrapped structures.

The foregoing and other objects and features ofthe invention will bemade fully apparent to those skilled in the art from a consideration ofthe following detailed description taken in conjunction with theaccompanying drawings in which:

Fig. 1` is a perspective view, with parts in section and parts brokenaway, of the novel apparatus of this invention; i

Fig. 2 is a section taken on line 2-2 of Fig 1;

ig. 3 shows, on a reduced scale, an exploded perspective view of the jigstructure;

Fig. 4 is a vertical sectionthrough the jig structure; and

Figs. 5 and 6 show, on an enlarged scale, details of the anodestructure.

Referring to the drawings, the anode structure which is to beconstructed in accordance with the invention comprises an anode block Iof highly conductive material, such as copper. The block l has a centralopening extending therethrough providing a cylindrical cavity 2, whichcavity has an annular projection 3 intermediate the ends thereofl fromwhich projection a plurality of anode plates 4 and liextend inwardlytoward the axis of the cylindrical cavity. The outer edges of the plates4 and 4 are secured to the face of the annulaiprojection 3 by solderingand the inner edges thereof form a plurality of anode faces adapted tocooperate with a thermionic cathode to be positioned centrally of thecavity fin the free space adjacent the inner ends of the plates- 4 and4. As is well understood in the art, an even number of plates 4 and 4'are provided and the space between each pair of adjacent platesconstitutes a resonant cavity.

At points adjacent their inner edges, alternate anode plates 4 areelectrically connected together at the upper ends thereof by means of anouter `strap 5, while the intervening plates 4 are electricallyconnected by an inner strap 6. At the lower ends of the anode plates,the plates 4' are connected together by an outer strap 5 and the plates4 are connected by an inner strap 6'.. -It will be seen'that thestrapping arrangement at the lower end of each anode plate is thereverse of the strapping arrangementl at the top of the plate; in otherwords, where the plate is connected t0 the outer strap 5 at its upperend, the lower end is connected to the inner strap B and vice-versa.

In order that the straps 5-6l and 5'-6' may be alternately connected tothe anode plates or lpass freely adjacent thereto, as required by theabove construction, I provide a notch l in. one

the annular projection 3. Assuming that the plateisl to be one of theanode arms 4, it is inserted with the notch 8 at the lower end thereof,

- and in its lowermost position the plate will connotch 8having-,astepped portion Bf'gspaceld to accommodate the inner straps 6or 6. and the width and depth of this notch is such that the strap or 5'may pass freely therethrough without contacting the plate. The plates-4and 4' are identical in construction, but in assembly the position ofthe notches 'I and 8 is reversed. the.

plates 4 being positioned with the notch 1 at the upper end, while theplates 4' .are positioned with the notch 8 at the upper end.

In order to construct the anode arrangement as described above, Iprovide a jig 9 comprising a base I0 from which projects a support andpositioning member II. The support II has a lower cylindrical portion I2adapted to flt in a suitable bore in the base I0 and to be held uprightthereby.

Above the cylindrical portion I2 is an intermediate fiange I3 upon whichthe lower end of the anode block I is adapted to rest and to be centeredrelative tothe jig 9 by a shouldered portion I4 projecting into theopening 2 to a point y below the annular projection 3. An uppercylindrical portion I5 having a plurality of slots I6, extendinglongitudinally thereof, projects upwardly from the shouldered portionI4, concentric with the opening 2, for such a distance that the upperend of the cylindrical portion I5 will project above the annularprojection 3 of the anode block I when the latter is positioned on thejig. A central opening I1 extends through the support II having a lesserdiameter than the internal diameter of the cylindrical portion I5,leaving a shoulder I8 between said opening and the internal surface ofthe cylindrical portion I5, A mandrel I9 extends through the' opening I1and through the slotted cylindrical portion I5 to a -point above theupper end of said cylindrical portion, and is provided with splines 20extending from the upper end thereof, at least as far as the shoulderedportion I8. The outer diameter of the mandrel I9 is such that it makes asliding fit with the opening I1, and the internal diameter of the straps6 and 6 is substantiallir the same as the diameter of said mandrel, sothat these straps may be slipped on the mandrel and centered thereby.The outer'diameter of the straps 5 and 5 is approximately equal to theinternal diameter of the slotted cylindrical portion I5 so that thesestraps make a sliding fit with the interior surface 'of said cylindricalportion and may be -centered thereby. The depth of the splines 20 ismade equal to the. distance D between the inner edges of the plates 4and 4' and thestepped portion 8 of the notches 8.

In the manufacture of anode structures of the type described in theforegoing by means of my novel apparatus, the lower straps 5' and 8',which are of conductive material, such as copper, and preferably coatedwith solder for reasons which will hereafter more fully appear, are rstinserted in the jig between the slotted cylindrical portion I5 and themandrelml9 so that they rest on the internal shoulder I8 with the strap5 centered by the interior surface of the cylindrical portion I5 and thestrap-6 centered by the mandrel I9. One of the anode plates 4 or 4 isinserted into the opening 2, being guided by one of the slots I5 withits inner edge in one of the splines 20 and its outer edge in contactwith the surface of tact the strap B' at the stepped portion 8' of thenotch 8 and will be free and clear of the strap v 5,' as shown in Fig.5.

It will be understood that the number of slots I8 in the cylindricalportion I5 of the support II will correspondl to the number of anodeplates 4 and 4 desired in the anode structure, and a correspondingnumber of splines 20 will be provided inthe mandrel I9, and therefore ifone of the splines 20 is aligned with one of the slots I5,

`each of the other splines will be aligned with a corresponding slot I5.Accordingly, the next adjacent plate may be inserted in the nextadjacent spline and'will be guided into position by the correspondingslot I5. This plate is inserted with the notch 1 at the lower endthereof and the notch 8 at the upper end to provide one of the plates 4.In its lowermost position this plate will contact the strap 5' at thestepped portion 'I' of the notch 1 and will be free and clear of thestrap 6', as shown in Fig. 6.

, The next succeeding plate will be inserted with lthe notch 8 at thelower end thereof to provide one of the plates 4, and the succeedingplates will be inserted with the notches 'I and 8 alternately in thelowermost position.

In the instance shown, twelve of the plates 4 and 4 are provided, and itwill be understood that any even number of plates may be used. When all0f the plates 4 and 4' have been positioned in the jig, the strap 6 isinserted, being guided into position by the mandrel I9, and it 'will beseen that this strap will rest upon the stepped portion 8' of thenotches inthe plates 4', and its upper surface willbe flush with theupper edge of these plates. The strap 5 is inserted, being guided intoposition by the interior surface of the cylindrical portion I5, and itwill be seen that this strap will rest on the stepped portion I of thenotches 'I in each Aof the plates 4, the distance L between the inneredge of the plates and outer edge of the stepped portion 1' of the notch'I being equal to the distance from the base of any spline 20 to theinterior surface of the cylindrical portion I5.

The straps 5 an 6 are of conductive material and are preferably coatedwith solder, the same as straps 5' and 6'. The preferred solder for thispurpose is an eutectic alloy of silver and copper.

After the plates 4 and 4' and the straps 5, 5' and 6, 6 have beenassembled in the jig, as described in the foregoing, a weight 2l, havingan annular boss 22 projecting centrally therefrom, is placed on the jigto'holdl the parts in position for soldering.1 For this purpose theannular boss 22 has an internal diameter corresponding to the outerdiameter of 'the mandrel I9 and an external diameter corresponding tothe internal diameter of the slotted cylindrical portion I5, so thatwhen the weight is positioned on the jig the boss 22 will project intothe annular space between the mandrel I9 and the cylindrical portion I5,and bear at its lower end on the straps 5 and 6. The straps 5 and 6 aretamped into place by the boss and are held in the desired position inthe stepped portions 'I' -and 8', respectively, of the notches I and 8with the upper surfaces of the straps flush with the upper edges of theplates 4 and 4. The lower straps 5' and anarco 6' are similarlymaintained in position by the l shoulder Il. n

The parts of the assembly may now be secured together?= bysoldering. and-it is for this purpose I prefer that each of the straps I, and 6, 6' beprovided with a thin coating of solder, preferably an eutectic alloy oflsilver and copper.

The outer edges of the plates 4 and 4' may be provided with a thincoating of solder for securing the plates to the annular projection l ofthe block i, or preferably a thin ring of the solder may be placed at.the upper outer ends of the plates 4 and I' adjacent the cylindricalsurface of the annular projection 3. `The entire assembly may then beplaced in a furnace having a non-oxidizing atmosphere and heated to atemperature suiilcient to melt the solder. Ihe solder secures the strapsl, 'I' and 6, 8' to the plates l and 4' at the points ot contact in thestepped portions l' .and l of the notches 'l and 8, and i the outeredges of theV plates are secured to the cylindrical surface of theprojection 3. Where a ring of solder is provided adjacent the upperouter ends of the plates, as described, it is found that the solder onlmelting tends to flow down'- wardly along the lines of contact betweenthe cylindrical surface and theedges of the plates and iiil theinterstices therebetween.

' 2. An apparatus for assembling the component' directly opposite, inregister with, and radially In order to prevent the solder from unitingany parts of the anode assembly to the jig, all parts of the latter areprovided with surfaces to which the solder does not fuse. Preferably allparts of the jig arelmade of `or surfaced with stainless steel and thesurfaces oxidized. The solder does not unite with such a surface, andafter baking the completed anode assembly may be readily removed fromthe jig.

It will be seen that the iig structure above described and the procedureemployed provide an eillcient means and method for rapidly andaccurately assembling anode structures of the type described. Thesplines 20 and the slots I6 proyvide two spaced guides for each of theplates l, 4 and insure more accurate angular spacing of the plates whilefacilitating the ease with which they may be placed in position. Theutilization of the inner surface of the cylindrical portion I5 as aguide and centering means for the outer straps 5 and 5 and the outercircumference of the mandrel Is as a guide and centering means for theinner straps B and 6' insures that these straps will be accuratelyspaced and positioned without requiring great time, care or skill 'onthe part of the operator.

While there has been herein described a preferred form of the invention,other embodiments thereof within the scope of the appended claims willbe obvious to those skilled in the art from a consideration of the formshown.

What is claimed is:

1. An apparatus for assembling the component parts of the anode of anelectron-discharge de-v vice comprising: a central member having aplurality of splines dening a plurality ofslots extending longitudinallythereof; and a cylindrical member concentric with said central member;said cylindrical member having a plurality of slots extendinglongitudinally thereof; the slots of said cylindrical member, throughouttheir major extent, being directly opposite, in register with. andradially spaced from the slots of said central member.

spaced from the slots in said central member.

3. An apparatus for assembling the component parts of thev anode of anelectron-discharge device comprising: a base portion having a centralcylindrical bore; a cylindrical member having a *sliding fit in-saidcylindrical bore of said base portion; and a central member extendingthrough said cylindrical member and having a plurality of splinesdefining a plurality of slots extending longitudinally thereof; saidcylindrical member having an linternal wall spaced from said centralmember. and a plurality of slots extendinglongitudinally thereof; theslots of said cylindrical member, throughout their major extent, beingdirectly opposite, in register with, and radially spaced from the slotsin said central member.

4. An apparatus for assembling the component parts of the anode of anelectron-discharge device of the type having a plurality of plates projecting radially from the interior wall of a cylindrical cavity, andhaving alternate plates electrically connected adjacent the inner endsthereof by an annular ring of conductive material, comprising: a centralmember having a plurality of splines defining a plurality of slotsextending longitudinally thereof; and a cylindrical member concentricwith and spaced from said central member, and having a plurality ofslots extending longitudinally thereof; the slots of `said cylindricalmember throughout their major extent, being directly opposite, inregister with, and radially spaced from the slots in said centralmember; said central member having an outer 'diameter corresponding tothe internal diameter of said ring.

PALMER P. DERBY. WARREN M. ROBERTSON.

REFERENCES CITED The following references are of record in the file ofthis patent:`

UNITED STATES PATENTS OTHER REFERENCES A skin Game in Metallurgy,scientinc Amer.. June 1941, pages 331-332.

